Our neighborhood has monthly potluck parties, and it was my turn to host last month. I just happened to get a glimpse of a neighbor accidentally spilling his red wine on my sofa pillow. I saw him look around (he didn’t see me in the hallway) and then quickly turn the pillow over! I know it’s a party and these things happen, but I can’t believe that’s how he handled it. What would you do as the host?

-Seeing Red

Monk: He knows he did it. You know he did it. But he doesn’t know that you know he did it.

I suggest you surprise him with your shared knowledge — in a warm and friendly manner. Your goal is to subtly prompt him to do the right thing: apologize and offer to repair the damage.

Look for the opportunity to have a one-to-one neighborly chat and mention how much you and your husband enjoyed the neighborhood get-together at your house. Make good eye contact. Wait for it … and if you hear crickets chirping after three seconds (not a second more as he may be ready to sprint), say, “We’re looking forward to having everyone over again, but next time you’ll all be drinking chardonnay out of sippy cups because we never could get those red wine stains out of the sofa pillow.”

Hobie: If you had caught him in the moment, it would have been perfectly fine to swoop in and say, “Oh, George, don’t worry. It’s the sign of a great party!” And then whisk away the pillow to be saved or not. In that scenario, he likely would have apologized and offered to pay for the damage (and you could have thanked him and turned him down).

But after the fact, take Monk’s advice only if you can carry it off without sounding petty or suspicious. After all, he may have failed the etiquette test in the moment, but in the greater scheme of neighborhood life, hosts assume the risk of (minor) damages and don’t make their guests feel guilty or unwelcome, even after the fact.